The use of synthetic cannabinoids (SC), commonly referred to as `Spice,' is increasing at an alarming rate. In spite of such widespread human use there have been no studies directly investigating the abuse liability of SCs in laboratory animals. We propose studies in male and female non-human primates (NHPs) to assess the behavioral and physiological risks of 3 SCs (JWH018, JWH-073, and HU-210) relative to delta9-tetrahydrocannabinol (THC). The clinical significance of our proposal is enhanced by our use of cannabinoid vapors in a self-administration paradigm; the administration route most relevant to human cannabinoid abuse. Aim 1a. Reinforcing Efficacy: Compare the reinforcing effects of THC and JWH-018 vapors using our established methods of vapor self-administration. Aim 1b. Drug Substitution. Determine if a history of THC self-administration affects SC self-administration by examining the ability of 3 SCs and THC to maintain self- administration in one group of monkeys trained to inhale THC and in another group of monkeys trained to inhale JWH-018. Aim 2. Medication Model: Establish a paradigm for probing pharmacotherapies for cannabinoid-use disorders (CUD) using our established vapor vs. non-drug choice procedures. The effects of 1) a compound that increases oxytocin release (SOC1), 2) a hypocretin antagonist (SB334867), and 3), as a positive control, the CB1 antagonist rimonabant will be compared in monkeys trained to self-administer THC and monkeys trained to self-administer JWH-018. Aim 3. Chronic Exposure: Establish the physiological and behavioral effects of chronic exposure to experimenter-delivered JWH-018, JWH-073, HU-210, and THC vapor. After determining dose-response functions for physiological, e.g., heart rate, and operant effects of the SCs and THC, we will expose animals to equipotent doses of the 4 drugs thrice a day for 4 weeks (1 drug/phase). We will measure the effects of rimonabant-precipitated withdrawal at the beginning and at the end of 4 weeks for each of the 4 drugs. Aim 4. Novel Compound Evaluation: Given the continuous development of new SCs, one group of monkeys will be trained to assess the reinforcing effects of up to 3 novel SCs that emerge over the first 2.5 years of this proposal, or we will test other compounds currently identified in Spice that appear with increased frequency. Impact: SC use is a public health concern with minimal preclinical data available. The proposed studies are designed to fill a critical gap in our knowledge regarding the risks of these drugs in a species (non-human primates) and route of administration (vapor inhalation) with direct clinical relevance. The findings will 1) inform and predict the risks associated with SCs as they emerge on the drug market, 2) establish a preclinical model for testing potential therapeutic approaches for CUD and SC disorders, and 3) provide methods for laboratory studies using the increasing popular route of vapor delivery, i.e., vaping.